General Description: The outdoor map measurer is a lightweight and portable tool, perfect for outdoor activities such as camping, hiking, cycling, and hunting. Its mini metal handle provides an easy grip and comfortable use. The high-quality metal and plastic casing makes it sturdy, wear-resistant, and rainproof, ensuring its durability. This tool allows you to quickly calculate the distance between two points on a map by rolling the small metal wheel; the pointer indicates the exact scale. Technical Specifications: Material: Aluminum + ABS + Acrylic; Color: Black; Product Size: 9.5 x 4.5 cm (3.74 x 1.77 inches). Usage: To use the measurer, simply place the small metal wheel on the map and roll it. The pointer will indicate the exact scale. It is recommended to use it horizontally to ensure accuracy. Avoid using it near magnetic objects or barbed wire to prevent interference with the magnetic needle. Other Information: Do not wipe with a cloth or dirty hands. When not in use, close it and store it away from ferromagnetic materials to prevent loss of magnetism.